The processing of silver halide color photographic materials comprises a bleaching step and a fixing step.
Examples of known useful bleaching agents include ferricyanides, bichromates, persulfates and iron salts of aminopolycarboxylic acid. However, there are disadvantages with these bleaching agents. For example, ferricyanides and bichromates have high toxicity though they have high bleaching ability. Persulfates and iron salts of aminopolycarboxylic acid have low bleaching ability though they have low toxicity and a solution containing them cannot be easily reused.
Ferric salts are excellent bleaching agent, because they are cheap and have low toxicity and high bleaching ability and it is easy to regenerate a spent bleaching solution containing these salts. These bleaching agents have been described in Japanese Patent Publication No. 14035/70, Japanese Patent Application (OPI) No. 16534/75 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") and British Pat. No. 1,464,127. However, when ferric salts are carried in the fixing solution it causes a great deal of fatigue of the fixing solution. Further, when these salts remain in the photographic materials cause yellow stains deteriorating the stability of the images. Therefore, in order to prevent the above described disadvantages, water wash is carried out after processing with the bleaching solution, or fixation is carried out after processing with a bath of organic aicd, phosphoric acid or organophosphonic acid when the water wash is insufficient. (Japanese Patent Application (OPI) No. 36126/75 and German Patent Application (OLS) No. 2,732,153.) However, the above described processing is by no means preferable, because it is contrary to the recent requirements of increasing the processing rate, eliminating the discharge of the processing solutions, and the economization of water.